| 摘要 |
<p>A valve comprises a housing formed from parts 1 and 2. An operating shaft 3 is rotatably mounted in the housing part 1 and carries a metal valve gate 4 which slides in continuous metal to metal contact on a metal valve seat 5. Seat 5 forms part of a valve chamber 6 having an inlet 7 and outlet 8. Valve gate 4 incorporates a port which can be moved into communication with outlet passageway 8 upon rotation of the shaft 3. Shaft 3 is rotated by means of an external tee-bar 10. Shaft 3 has an angled shoulder 13 which provides a metal to metal seal against an angled seat of the housing part 1. Metal gate buttons (21, figure 6) may be provided to give a continuous metal to metal sealing contact with the seat. A metal lip 16 which acts as a seal may be provided on one of the housing parts. The lip is acted on by internal pressure to enhance sealing.</p> |
